Conventionally, there is an information processing system in which a plurality of nodes having one or a plurality of CPUs and a shared memory are connected by a crossbar, and the shared memories in each of the nodes can be accessed by a CPU in another node. There has been proposed a technique for controlling access in such an information processing system by using memory tokens set to each of a plurality of regions included in the shared memory and access tokens which are added to a request from a CPU in another node for accessing a region having a memory token set thereto. Specifically, when a shared memory is accessed, the memory access in the request is permitted if the memory token and the access token added to the request match. According to this technique, permission for access from another node can be controlled for each region included in the shared memory.
Japanese Laid-Open Patent Publication No. 2013-140446 is an example of a related prior art document.